company prep

Bloomberg

Problems frequently reported at Bloomberg, in course order. Solve the must-dos first.

52 easy95 medium11 hardTwo pointers (opposite ends) ×9 In-place linked-list rewiring ×9 Hash lookup (seen before?) ×9 String parsing ×7 Frequency counting ×7 Tree BFS (level order) ×7

02 · Arrays & Strings in Java

#58Length of Last WordEasy
#1929Concatenation of ArrayEasy
#387First Unique Character in a StringEasymust-do
#1512Number of Good PairsEasy

06 · Mindset & Problem Solving

#1480Running Sum of 1d ArrayEasy
#412Fizz BuzzEasy

07 · Big-O & Complexity

#69Sqrt(x)Easy

08 · Recursion

#509Fibonacci NumberEasymust-do
#344Reverse StringEasy
#24Swap Nodes in PairsMedium
#50Pow(x, n)Mediummust-do
#779K-th Symbol in GrammarMedium

09 · Math & Number Theory

10 · Arrays & Strings

#121Best Time to Buy and Sell StockEasymust-do
#122Best Time to Buy and Sell Stock IIMedium
#169Majority ElementEasymust-do
#238Product of Array Except SelfMediummust-do
#242Valid AnagramEasymust-do
#14Longest Common PrefixEasy
#189Rotate ArrayMedium
#31Next PermutationMediummust-do
#41First Missing PositiveHardmust-do

11 · Matrices & Simulation

#48Rotate ImageMediummust-do
#73Set Matrix ZeroesMediummust-do

12 · Two Pointers

#125Valid PalindromeEasymust-do
#153SumMediummust-do
#163Sum ClosestMedium
#11Container With Most WaterMediummust-do
#42Trapping Rain WaterHardmust-do
#27Remove ElementEasy
#26Remove Duplicates from Sorted ArrayEasy
#80Remove Duplicates from Sorted Array IIMedium
#283Move ZeroesEasy
#88Merge Sorted ArrayEasymust-do
#392Is SubsequenceEasy
#75Sort ColorsMediummust-do

13 · Sliding Window

#643Maximum Average Subarray IEasy
#3Longest Substring Without Repeating CharactersMediummust-do
#424Longest Repeating Character ReplacementMediummust-do
#567Permutation in StringMediummust-do
#209Minimum Size Subarray SumMediummust-do

14 · Hashing & Prefix Sums

#1Two SumEasymust-do
#217Contains DuplicateEasymust-do
#205Isomorphic StringsEasy
#290Word PatternEasy
#128Longest Consecutive SequenceMediummust-do
#303Range Sum Query - ImmutableEasymust-do
#560Subarray Sum Equals KMediummust-do

15 · Linked Lists

#206Reverse Linked ListEasymust-do
#21Merge Two Sorted ListsEasymust-do
#141Linked List CycleEasymust-do
#19Remove Nth Node From End of ListMediummust-do
#142Linked List Cycle IIMediummust-do
#287Find the Duplicate NumberMediummust-do
#82Remove Duplicates from Sorted List IIMedium
#61Rotate ListMedium
#2Add Two NumbersMediummust-do
#138Copy List with Random PointerMedium

16 · Stacks & Monotonic Stack

#20Valid ParenthesesEasymust-do
#155Min StackMediummust-do
#739Daily TemperaturesMediummust-do
#496Next Greater Element IEasy
#84Largest Rectangle in HistogramHardmust-do
#394Decode StringMediummust-do
#735Asteroid CollisionMediummust-do

17 · Queues & Deques

#232Implement Queue using StacksEasymust-do
#225Implement Stack using QueuesEasy

18 · Binary Search

#35Search Insert PositionEasymust-do
#34Find First and Last Position of Element in Sorted ArrayMediummust-do
#74Search a 2D MatrixMedium
#33Search in Rotated Sorted ArrayMediummust-do
#153Find Minimum in Rotated Sorted ArrayMediummust-do
#875Koko Eating BananasMediummust-do
#162Find Peak ElementMediummust-do
#4Median of Two Sorted ArraysHard

19 · Sorting

#274H-IndexMedium

20 · String Parsing & Expression Evaluation

#13Roman to IntegerEasymust-do
#12Integer to RomanMedium
#151Reverse Words in a StringMediummust-do
#8String to Integer (atoi)Mediummust-do
#227Basic Calculator IIMediummust-do
#224Basic CalculatorHardmust-do

21 · Tree Traversals

#94Binary Tree Inorder TraversalEasymust-do
#102Binary Tree Level Order TraversalMediummust-do
#199Binary Tree Right Side ViewMediummust-do
#103Binary Tree Zigzag Level Order TraversalMedium
#117Populating Next Right Pointers in Each Node IIMedium
#662Maximum Width of Binary TreeMedium
#863All Nodes Distance K in Binary TreeMediummust-do

22 · Tree Recursion

#104Maximum Depth of Binary TreeEasymust-do
#110Balanced Binary TreeEasy
#100Same TreeEasy
#226Invert Binary TreeEasymust-do
#101Symmetric TreeEasymust-do
#112Path SumEasy
#113Path Sum IIMediummust-do
#222Count Complete Tree NodesMedium
#543Diameter of Binary TreeEasymust-do
#105Construct Binary Tree from Preorder and Inorder TraversalMedium
#106Construct Binary Tree from Inorder and Postorder TraversalMedium

23 · Binary Search Trees

#700Search in a Binary Search TreeEasy
#701Insert into a Binary Search TreeMedium
#450Delete Node in a BSTMediummust-do
#98Validate Binary Search TreeMediummust-do
#230Kth Smallest Element in a BSTMediummust-do
#235Lowest Common Ancestor of a Binary Search TreeMediummust-do
#220Contains Duplicate IIIHard

24 · Heaps & Priority Queues

#1046Last Stone WeightEasy
#692Top K Frequent WordsMedium

25 · Tries

#421Maximum XOR of Two Numbers in an ArrayMedium

26 · Graphs: BFS & DFS

#200Number of IslandsMediummust-do
#695Max Area of IslandMediummust-do
#133Clone GraphMediummust-do
#130Surrounded RegionsMedium
#1730Shortest Path to Get FoodMedium
#909Snakes and LaddersMedium
#433Minimum Genetic MutationMedium

28 · Union-Find & Minimum Spanning Trees

#547Number of ProvincesMediummust-do

29 · Topological Sort

#329Longest Increasing Path in a MatrixHardmust-do

30 · Advanced Graphs: Euler Paths, Bridges & SCCs

#399Evaluate DivisionMediummust-do

31 · Backtracking

#78SubsetsMediummust-do
#90Subsets IIMediummust-do
#46PermutationsMediummust-do
#22Generate ParenthesesMediummust-do
#79Word SearchMediummust-do
#131Palindrome PartitioningMedium

32 · Greedy Algorithms

#55Jump GameMediummust-do
#45Jump Game IIMediummust-do
#134Gas StationMediummust-do

33 · Intervals

#252Meeting RoomsEasy
#56Merge IntervalsMediummust-do
#435Non-overlapping IntervalsMediummust-do
#253Meeting Rooms IIMediummust-do

34 · Bit Manipulation

#136Single NumberEasymust-do
#268Missing NumberEasymust-do

35 · Dynamic Programming

#70Climbing StairsEasymust-do
#746Min Cost Climbing StairsEasy
#139Word BreakMediummust-do
#322Coin ChangeMediummust-do
#518Coin Change IIMedium
#377Combination Sum IVMedium
#62Unique PathsMediummust-do
#63Unique Paths IIMedium
#120TriangleMedium
#72Edit DistanceMediummust-do
#5Longest Palindromic SubstringMediummust-do

36 · DP Patterns

#309Best Time to Buy and Sell Stock with CooldownMediummust-do
#714Best Time to Buy and Sell Stock with Transaction FeeMedium
#123Best Time to Buy and Sell Stock IIIHard
#115Distinct SubsequencesHard

37 · Design Data Structures

#380Insert Delete GetRandom O(1)Mediummust-do

38 · Segment Trees, Fenwick & String Matching

#307Range Sum Query - MutableMediummust-do
#315Count of Smaller Numbers After SelfHardmust-do
#28Find the Index of the First Occurrence in a StringEasymust-do
#459Repeated Substring PatternEasy
#214Shortest PalindromeHard